The prior art contains agricultural techniques designed to promote the growth of plants. For example, U.S. Pat. No. 3,845,584, in the name of Frank B. Mercer, teaches the use of a bi-level plastic net bonded atop an impermeable plastic sheet for growing grass. U.S. Pat. No. 3,863,388 teaches a similar bi-level net and impermeable sheet upon which a layer of rooting medium containing seed may be spread and which thereupon encourages germination and growth of the seeds.
The use of dark plastic sheeting spread over the ground has been found to retard plant growth. Whenever holes or tears occur in the sheeting, as commonly happens in outdoor use, plants tend to grow through the openings thus created. In addition, the fully impermeable sheet cuts off water entry to the areas covered by it.
The prior art fails to disclose a multiple purpose blanket which simultaneously discourages unwanted growth while encouraging desireable plants.